Hi, I am running two hosts with xen-4.0.1 and dom0 kernel 2.6.32.41. The two hosts are connected to a Gigbit switch. Then I use iperf to measure the bandwidth and got the results of 200Mbit/second, which is only 1/5 of the available bandwidth. Then I boot these two hosts using a vanilla kernel of 2.6.32.34. The iperf reports 937Mbis/s, which is very close to the available link bandwidth. So why the pvops dom0 kernel performs so bad? Does anyone observe similar problem? Thanks. - Hui _______________________________________________ Xen-devel mailing list Xen-devel@lists.xensource.com http://lists.xensource.com/xen-devel
Konrad Rzeszutek Wilk
2011-Jul-15 18:19 UTC
Re: [Xen-devel] dom0 kernel v2.6.32.41 network problem
On Fri, Jul 15, 2011 at 05:54:11PM +0000, Hui Kang wrote:> Hi, > I am running two hosts with xen-4.0.1 and dom0 kernel 2.6.32.41. The two hosts are connected to a Gigbit switch. Then I use iperf to measure the bandwidth and got the results of 200Mbit/second, which is only 1/5 of the available bandwidth. > Then I boot these two hosts using a vanilla kernel of 2.6.32.34. The iperf reports 937Mbis/s, which is very close to the available link bandwidth. > So why the pvops dom0 kernel performs so bad? Does anyone observe similar problem? Thanks.Weird. No idea - I get around 911Mb/s with my dom0 - which is 3.0.0-rc7. Do you have some debug options turned on?> > - Hui> _______________________________________________ > Xen-devel mailing list > Xen-devel@lists.xensource.com > http://lists.xensource.com/xen-devel_______________________________________________ Xen-devel mailing list Xen-devel@lists.xensource.com http://lists.xensource.com/xen-devel
On Fri, 2011-07-15 at 19:19 +0100, Konrad Rzeszutek Wilk wrote:> On Fri, Jul 15, 2011 at 05:54:11PM +0000, Hui Kang wrote: > > Hi, > > I am running two hosts with xen-4.0.1 and dom0 kernel 2.6.32.41. The two hosts are connected to a Gigbit switch. Then I use iperf to measure the bandwidth and got the results of 200Mbit/second, which is only 1/5 of the available bandwidth. > > Then I boot these two hosts using a vanilla kernel of 2.6.32.34. The iperf reports 937Mbis/s, which is very close to the available link bandwidth. > > So why the pvops dom0 kernel performs so bad? Does anyone observe similar problem? Thanks.It is definitely worth checking that you don''t have any debug options enabled in your kernel .config. Some of those options are far more expensive under Xen than native. (unfortunately I''m drawing a blank on precisely which options we''ve seen this with right now, anything to do with debugging page allocations etc would be a good bet). Ian. _______________________________________________ Xen-devel mailing list Xen-devel@lists.xensource.com http://lists.xensource.com/xen-devel